1. Field of the Invention
The present invention relates to a color photographic processing method. More particularly the present invention is concerned with a method for removing a fogging material formed in a color developer with the lapse of time or formed therein by regeneration of the color developer by passing the fogging material through a hydrophobic porous diaphragm.
2. Description of the Prior Art
Aromatic primary amines, especially p-phenylenediamine derivatives are generally used as developing agents for use in color developers. Representative examples of these aromatic primary amines are N,N-diethyl-p-phenylenediamine, 4-diethylamino-2-methylaniline, 2-methyl-4-[N-ethyl-N-(.beta.-hydroxyethyl)amino]aniline, 2-methyl-4-[N-ethyl-N-(.beta.-hydroxyethyl)amino]aniline and the like.
Color developers containing these aromatic primary amines as developing agents cannot contain a large amount of sulfites as preservatives (antioxidants), which is different from the situation with black-white developers containing N-alkyl-p-aminophenols or hydroquinones as developing agents, because a large amount of sulfites inhibits the coloring reaction between the aromatic primary amine developing agents and color couplers. Therefore, in a color developer containing an aromatic primary amine as a developing agent, hydroxylamine is generally used in combination with a sulfite as an antioxidant. However, since the decomposition of hydroxylamine is markedly accelerated owing to the presence of iron ions and copper ions, it is essential for a color developer containing hydroxylamine as a preservative to contain therein masking agents for heavy metal ions.
Aminopolycarboxylic acids such as nitrilotriacetic acid, ethylenediamine tetraacetic acid and the like are known as masking agents for heavy metal ions. They have, however, defects in that they themselves or the chelates thereof with heavy metal ions accelerate the decomposition of hydroxylamine. While 1,3-diamino-2-propanol tetraacetic acid described in U.S. Pat. No. 2,875,049 and diethylenetriamine tetraacetic acid described in U.S. Pat. No. 3,462,269 decompose hydroxylamine to a relatively lesser extent, they are not satisfactory. When a developer is allowed to stand for a long period of time or running (the term "running" herein used means continuous developing processing) is continued, the hydroxylamine contained in the developer decomposes, causing fogging and/or color mixing in a light-sensitive element after developing processing. Several materials have been reported to cause fogging or color mixing [see, for example, P. J. Mutter, Phot. Sci. Eng., 849 (1964)], but this, however, is a matter of conjecture.
A wide variety of photographic processing solutions are used to develop a silver halide photographic light-sensitive material exposed to light. A photographic processing solution having the most suitable composition is selected depending on the kind of silver halide photographic light-sensitive material to be processed. This developing solution exhibits the most desired developing capability under the conditions where the concentration of each component contained therein is maintained within a specific range. During the developing processing of a light-sensitive material, however, some of the components contained in the developer are consumed, whereas the concentration of other components increases due to components leaching out of the photographic light-sensitive material. In this way, the composition of the developer gradually changes, resulting in a decrease in development capability.
In order to enable a photographic processing solution to be used repeatedly by restoring the reduced processing capability thereof, a supplemental solution is generally added to the fatigued photographic processing solution after processing a predetermined number of photographic light-sensitive materials. This method of adding a supplemental solution can be used to supply the components consumed, but fails to reduce the components whose concentration has increased.
In general, when a supplemental solution is added, a photographic processing solution to be regenerated is withdrawn in the same amount as that of the supplemental solution added, for example, by overflowing, so that the amount of the processing solution in the processing vessel is kept constant. This withdrawal of the processing solution can be used to somewhat decrease the concentration of undesired components whose concentration has increased. Reduction of the concentration of the undesired components to the desired level requires the withdrawal of a large amount of the processing solution, however.
With regard to a developer, the halogen ion concentration contained therein increases as the developing processing is carried out. Of the halogen ions, bromine ion, has a great influence on the processing capability of a processing solution; that is, an increase in bromine ion concentration in the developer markedly decreases the rate of development. On the other hand, the chlorine ion concentration also increases, but an increase in chlorine ion concentration has substantially no adverse influence on the processing capability of the developer. As a result, the influence of the bromine ion concentration on the developer is great and is taken seriously.
In an automatic developing machine for processing a large number of photographic light-sensitive materials continuously and rapidly, it is necessary for the developing processing to always be stable and the processing capability is kept constant so that the same photographic characteristics are always obtained. Thus the processing capability of a developer, whose developing capability is decreased due to the developing processing of photographic light-sensitive materials, is restored by adding a supplemental solution to the developer. It is, however, quite difficult to control the increase in bromine ion concentration, which significantly influences the developer, even though a part of the developer is withdrawn by overflowing, for example. Therefore, to restore the processing capability of a developer for re-use, the components consumed during the development must be supplemented and, at the same time, the concentration of bromine ion adversely influencing the developing effect must be decreased to below a certain level.
As can be understood from the above explanation, it is necessary for not only the components consumed during the development and necessary for the development to be supplemented, but also the bromine ion, which increases in concentration during the development and adversely influences the developing effect, to be removed.
Thus a method of removing bromine ion from the fatigued developing solution by the use of an ion exchange resin (e.g., as disclosed in Journal of the SMPTE, Vol. 65, 478 to 484; Vol. 66, 64 to 65), a method of removing bromine ion by electrodialysis using an ion exchange film (e.g., as disclosed in Bulletin of the Society of Scientific Photography of Japan, No. 18, December (1968), pp. 38 to 44), a method of removing bromine ion by electrolysis, etc., are known.
In accordance with the method of removing halogen ions by electrolysis, a fatigued developer is introduced into a cathodic cell of an electrolytic cell in which the cathodic and anodic cells are formed by placing an anion exchange film between a cathode and an anode, and an electrolyte is introduced into the anodic cell, and then an electric current is passed between the electrodes to effect electrolysis, thus removing halogen ions.
While the above described methods can be used to effectively remove the halogen ions, other components present in the developer are decomposed during regeneration such as by electrolysis, etc., due to an electrochemical action. As a result, those components causing fogging and/or color mixing in a photographic image are formed. These fogging and/or color mixing components are formed to a great extent when the color developer contains hydroxylamine. Therefore, when a processing solution which has been used for a long period of time and is fatigued, and which already contains fogging components, is regenerated, the concentration of the fogging components increases. In regeneration using an ion exchange resin, the developer components are rarely decomposed during regeneration. However, those components decomposing gradually accumulate in a large amount by repeated regeneration processing, thereby causing fogging and/or color mixing in a photographic image.
As described above, with color developers, particularly those color developers containing hydroxyamines, the removal of fogging and/or color mixing components, which are formed by allowing the developer to stand for a long period of time after incorporation of heavy metal ions or by running the developer, or which are formed by regeneration of the developer such as ion exchange, electrolysis, electrodialysis, or the like, is essential for obtaining a high quality image.